Hand-operated jig-saw with saw blade guidance system

ABSTRACT

A power scroll saw with a housing and a saw blade capable of being driven in a reciprocating manner, and with tongs-like guides that guide the saw blade in a laterally-supported manner is capable of being used in a variety of work applications due to the fact that the guide means are capable of being switched by hand selectively into a position having lateral clearance from the saw blade and into a position in which they laterally support the saw blade.

BACKGROUND INFORMATION

The present invention is relates to a power scroll saw 1.

A power scroll saw with saw blade guidance system is made known in WO02/22297, which guides the flat sides of the saw blade between twolateral clamping jaws. According to the invention, the clamping jaws arecontrolled using a servomotor.

SUMMARY OF THE INVENTION

The present invention has the advantage that the guide system isselectively activated and/or deactivated.

In addition, the clamping means—which automatically adjust to theposition of the saw blade—have the advantage that the two flat sides ofthe saw blade are guided with matching, minimal bearing force, andundesirably high friction forces between the guide means and the sawblade are prevented.

Due to the fact that the guide means are elastically situated in such amanner that they attempt to move into the activated position bearing onthe saw blade, an abrupt activation of the guide means is selectivelypossible in the deactivated position as soon as the working conditionsrequire this. Due to the fact that a push-button is provided that, whenit is actuated, the clamping means move into their activated position ofsupporting the saw blade, activation of the guide means is particularlyconvenient.

Due to the fact that an actuation means for deactivating the guide meansis located on the saw blade clamping mechanism, the guide means areautomatically deactivated when the saw blade is replaced or removed.

Due to the fact that the chuck lever serving as actuating lever formoving the guide tongs into the “open” position for removing or clampingthe saw blade is provided with wedge means, in particular a ramp, withwhich the driving pin, together with the sliding members, is capable ofbeing displaced downward, a reliable, robust actuating mechanism fordeactivating the guide means is created.

Due to the fact that two sliding members for closing and/or opening thetongs-like guide means are supported such that they are relativelyparallel to each other and are displaceable along a straight line,whereby one sliding member forcibly carries along the other in adirection of travel and is capable of being moved back in the oppositedirection of travel independently of the sliding member that was carriedalong, simple and robust machine elements are used that ensure a highlevel of reliability of the power scroll saw.

Due to the fact that spring-preloaded sliding members, with slide guideslots, overlap lobes of the guide means, in particular guide jaws, asimple and reliable actuating mechanism is created for closing and/oropening the guide tongs. Due to the fact that the sliding members arecapable of being displaced, coupled together, in such a manner that acertain amount of play relative to each other exists along theirdisplacement path, a self-orienting positioning of the clamping jawsrelative to the saw blade is possible, with which deviations in the sawblade position from the ideal position are tolerated. This is achievedby situating a driving means between the first and second slidingmember, whereby, in the “closed” position of the guide tongs, an axialclearance of approximately 0.5 mm exists between the driving means andthe second sliding member in the direction of displacement toward the“open” position.

Due to the fact that the slide guide slots of the sliding members aresituated at an angle relative to vertical compared to the glide bolt ofthe tong jaws in the self-locking range, in particular 5 to 6 degrees ofinclination from vertical, the clamping jaws are capable of being closedwith a high amount of holding force, so that the clamping tongs cannotbe opened by external forces and/or if the saw blade bears against itwith a high amount of force.

Due to the fact that a finger protection mechanism is mounted on thehousing, the risk of injury when working with the power scroll saw ismarkedly reduced, and the U-shaped configuration of the fingerprotection mechanism allows the saw blade to be easily discernable andguidable in a controlled manner.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic depiction of a first exemplary embodiment ofthe invention,

FIG. 2 shows a side view of a second exemplary embodiment of theinvention,

FIG. 3 shows the assembly of the guide means,

FIG. 4 shows a cross section with inside view, from behind, of the guidemeans,

FIG. 5 shows the guide means in the closed position, and

FIG. 6 shows the guide means in the open position.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a schematically depicted, handheld reciprocating saw 10 atan angle from above, which accommodates a not-shown electric motor witha gearset in a housing 12 for the reciprocating driving of areciprocating rod 16. A saw blade 18 is detachably but captively coupledto reciprocating rod 16 with its clamping end, the saw blade passingdownward—as shown in the figure—through a base plate 14 of reciprocatingsaw 10.

Saw blade 18 bears—with its saw blade back 23, which is diametricallyopposed to toothed side 17—against a support roller 22 that, oscillatingback in forth in feed direction 19, can impart a reciprocating motion tosaw blade 18, being energizable as necessary.

In addition, guide means configured as guide tongs 26 extend in front oftoothed side 17 of saw blade 18 above base plate 14, the guide meansbeing capable of supporting saw blade 18 on its flat sides in adiametrically opposed manner.

Using spring tension, a distance between guide jaws 24, 25 of guidetongs 26 is capable of being adapted to the particular thickness ofclamped saw blade 18. Guide jaws 24, 25 are capable of being pivotedaround a rotation point 30 (FIG. 4) between the dosed position and theopen position. In the closed position, the outermost ends of guide jaws24, 25 bear laterally against the flat sides of the saw blade.

The lower end of reciprocating rod 16 is equipped with a clamping device20 in which the clamping end of saw blade 18 is capable of being clampedin a captive manner and is capable of being detached by actuating achuck lever 21. When chuck lever 21 is actuated, guide tongs 26 areswitched to the open position, whereby this position is capable of beingselectively changed to the closed position—in which guide jaws 24, 25bear against saw blade 18—by actuating a side button 52.

FIG. 2 shows a further exemplary embodiment of a reciprocating saw 100,which conforms, in principle, with that according to FIG. 1, the guidetongs 260 of which, however, extend laterally relative to support roller220 and, as shown in the figure, are angled to the right, so that itextends behind reciprocating rod 160 and into the interior of housing120. As shown in the figure, a U-shaped protective frame 27 extendsparallel with said reciprocating rod from top to bottom, attached tohousing 120, the protective frame serving as finger protection againstaccidental contact with saw blade 180 and protecting the operator ofreciprocating saw 100 from injury.

Housing 120 is capable of being coupled with a base plate 140 in apivoting manner, and saw blade 180 is capable of being supportedlaterally by guide jaws 240, 250. A chuck lever 210 is situated abovethe region where reciprocating rod 160 exits housing 120, which iscapable of being pivoted to the left, as viewed in thefigure-transversely across the front region of housing 120-to remove sawblade 180. A push-button 520 is situated below operating lever 210; whenit is actuated, guide tongs 260 close abruptly to laterally support sawblade 180.

A pivoted lever 15 for adjusting the reciprocating stroke of pendulumroller 220 is provided behind push-button 520, as viewed in the figure.

The functional elements that are explained in FIG. 1 and areequally-acting and identically configured in FIG. 2 have the samereference numerals as in FIG. 1, but with a zero added at the end.

FIG. 3 shows the assembly of guide tongs 260 in their position relativeto reciprocating rod 160 and pendulum roller 220. It is clear that guidejaws 240, 250 extend—angled horizontally—from toothed side 170 of sawblade 180 rearward toward pendulum roller 220 and, angled once more,vertically upward, are coupled at rotation point 30 so as to be securedto the housing. Mounted on each guide jaw 240, 250 is a glide bolt 35,36—which extends toward the front out of the viewing plane—each of whichpasses through a slide guide slot 38, 39 of two sliding members 45, 46,which are displaceable upward and/or guided to the bottom left. Slideguide slots 38, 39 extend with an approximately 5-degree inclinationfrom the vertical and/or toward the axis of reciprocating rod 160, sothat, when sliding members 45, 46 are slid upward—as viewed in thefigure—guide bolts 35, 36 are displaced outwardly and, with thisdisplacement, guide jaws 240, 250 pivot outwardly and open. If slidingmembers 45, 46 are slid dowward, slid guide slots 38, 39 carry guidebolts 35, 36 along with them in such a manner that said guide bolts movetoward each other, so that guide tongs 260 close and the lower ends ofguide jaws 240, 250 bear laterally against saw blade 180. Slidingmembers 45, 46 are elastically preloaded by compression springs 42, 43(FIGS. 5, 6) and attempt to press sliding members 45, 46 axially upward.

Mounted on the axial extension of push-button 520 is a sliding elementthat extends—on a lobe 56 in the upper region of sliding member45—toward push-button 520. In FIG. 3, push-button 520 is slid toward theleft—as viewed in the figure—whereby it bears against a compressionspring 53 and has displaced its sliding element 54 in the “released”position relative to lobe 56. As a result, sliding member 45 can beabruptly displaced into its upwardly oriented position, whereby itreleases the second sliding member 46 that is pressed downward with itsdriving pin 48. When actuating lever 210 is pivoted toward the left—asviewed in the figure—an arm on which a ramp 50 is mounted, the arm beingrigidly coupled with said actuating lever—is rotated approximatelycentrally around the axis of reciprocating rod 160, whereby driving pin48 and the two sliding members 45, 46 are pressed downward. Slidingmember 54 reaches its locked position relative to lobe 56 as soon assaid lobe is slid downward together with sliding member 45. Lobe56—which previously was holding sliding member 54 in its closedposition—thereby releases sliding member 54 again, so that push-button520—preloaded by compression spring 53—is capable of being displacedinto its open position again, in which lobe 56 is locked in the verticaldirection of motion by sliding member 54.

FIG. 4 shows a cross section of power scroll saw 100 in the region ofguide tongs 260 as viewed from the rear, whereby rotation point 30 ofguide jaws 240, 250 is particularly clearly visible, and is formed by astud. Sliding members 45, 46—which are partially covered by guide jaws240, 250—are slid into their position vertically upward, so that guidetongs 260 are in the closed position. Ramp 50 has thereby releaseddriving pin 48 end, with this, sliding member 45 shown an the left inthe figure, which is followed by shorter sliding member 46. Driving pin48 is captively pressed into longer sliding member 45 in a bore (notshown in greater detail) transversely to its direction of displacement,whereby it partially penetrates, with its exposed end, a groove-likerecess (not shown in greater detail) in the upper front side of shortersliding member 46.

Push-button 520 remains in its inwardly-pressed position as long assliding member 45 remains in its vertically uppermost position. Glidebolts 35, 36, the rear views of which are visible in guide jaws 240,250, are thereby pivoted toward each other, so that guide tongs 260 arein the closed position.

FIG. 5 shows guide tongs 260 in their closed position, in which slidingmembers 45, 46 are upwardly displaced and lobe 56 locks sliding member54 in place, so that push-button 520 remains pressed axially inwardly.As long as chuck lever 210 is pivoted to the left—as viewed in thefigure—ramp 50 glides in a wedge-like manner toward driving pin 48, sothat, as described previously, sliding members 45, 46 are displaceddownwardly—as viewed in the figure—and the clamping tongs are opened.

FIG. 6 shows guide tongs 260 according to FIG. 5 in the open position,because sliding members 45, 46 are slid vertically downward againstcompression springs 42, 43, thereby spreading apart guide bolts 35, 36and, therefore, guide jaws 240, 250. Lobe 56 has slid past slidingmember 54 to the right—as viewed in the figure—and has released saidsliding member from the preload force of compression spring 53—so thatpush-button 520 can be displaced into the open position to the right, asviewed in the figure. In this position, sliding member 54 is positionedabove lobe 56 and locks it and/or sliding member 45 in the upwarddirection of motion. Since sliding member 45 with its driving pin 48 atthe top bears against adjacent sliding member 46, this sliding member 46must follow the motion of driving pin 48 downward, acted upon by ramp50. In the closed position according to FIG. 4, driving pin 48 has avertical clearance of approximately 0.5 mm relative to sliding member46, so that driving pin 48 first must be pressed downward by this amountbefore sliding member 46 is acted upon and can follow the motion. As aresult, in the closed position, adjustments can be made within a certaintolerance range relative to the center position of saw blade 180. If sawblade 180, as a result of a center position, is closer to guide jaw 240,it will bear laterally against saw blade 180 first, displaced by slidingmember 46 and/or by guide bolt 35, so that adjacent guide claw250—adjusted by the free, upwardly movable, longer sliding member45—comes to rest at the side of saw blade 180 somewhat later. Due to theself-locking in slide guide slot 38, 39, slide guide bolts 35, 36 arepositioned in the locked position, and guide jaws 240, 250 cannot bemoved outwardly, into the position in which guide tongs 260 are open.If, as a result of an inclined position of saw blade 180, guide jaw 250is the first to comes to rest on saw blade 180 due to the upward motionof sliding member 45 and the inward displacement of guide pin 36 in theguide slot, the left—as viewed in the figure—guide jaw 240 must cover alonger actuating path, which it realizes by left sliding member 46 beingable to move toward driving pin 48 by the amount exceeding the amount ofapproximately 0.5 mm above its zero position, and thereby very securelycome to rest on the lateral surface of saw blade 180. A secure, uniformguidance of saw blade 180 is thereby ensured within the foreseeabletolerance range.

1. A power scroll saw (10, 100) with a housing (12, 120) and a saw blade(18, 180) capable of being driven in a reciprocating manner, and withtongs-like guide means (26, 260) that guide the saw blade (18, 180) in alaterally-supported manner, wherein the guide means (26, 260) arecapable of being switched by hand selectively into a position havinglateral clearance from the saw blade (18, 180) and into a position inwhich they laterally support the saw blade (18, 180), wharein the guidemeans (26, 260) attempt to move, with spring preload, into the positionin which they laterally support the saw blade (18, 180), wherein apush-button (52, 520) is provided, and when it is actuated, the guidemeans (26, 260) abruptly move into their position in which theylaterally support the saw blade (18, 180), wherein elastically preloadedsliding members (45, 46) guided along a straight line are provided forclosing and/or opening the tongs-like guide means (26, 260), wherein thetwo sliding members (45, 46) are supported such that they aredisplaceable relative to each other, whereby one sliding member (45)forcibly carries along the other (46) in a direction of travel and iscapable of being moved back in the opposite direction of travel, whereina driving means (48) is situated between the first sliding member (45)and the second (46), whereby, in the “closed” position of the guidetongs (26), an axial clearance of approximately 0.5 mm between thedriving means (48) and the second sliding member (46) exists in thedirection of displacement toward the “open” position.
 2. The powerscroll saw as recited in claim 1, wherein a further push-button (21,210) is provided; when it is actuated, the guide means (26, 260) moveinto their deactivated position with lateral release of the saw blade(18, 198), the guide means being lockable, with release capability, inthis position.
 3. The power scroll saw as recited in claim 1, wherein afurther push button (21) serving as actuating means (21) for moving theguide tongs (26) into the “open” position is provided with wedge means,in particular a ramp (50), with which the driving means (48), togetherwith the sliding members (45), is capable of being displaced downward.4. The power scroll saw as recited in claim 1, wherein the slidingmembers (45, 46), with slide slots (38, 39), overlap guide bolts (35,36) of guide jaws (24, 25) in such a manner that they open the guidetongs (26) when moved downward and they close the guide tongs (26) whenmoved upward.
 5. The power scroll saw as recited in claim 4, wherein theslide slots (38, 39) extend at such an angle to the guide bolts (35, 36)that only the sliding members (45, 46), when displaced, can displace theglide bolts (35, 36), but the guide bolts (35, 36) cannot displace thesliding members (45, 46).
 6. The power scroll saw (10) as recited inclaim 1, wherein a finger protection mechanism (27) extends on the frontside of the saw blade (18) parallel with said saw blade, toward the baseplate (14), the finger protection mechanism being captively fastened tothe housing (12).